What Is a Gene Mutation? Beginner Breakdown

Understanding What a Gene Mutation Is

A gene mutation is a change in the DNA sequence of a gene. These changes can be small or large and may affect how a gene works.

How Gene Mutations Happen

Copying mistakes: Cells sometimes make errors when copying DNA.

Environmental factors: Radiation, chemicals, or UV light can damage DNA.

Inherited changes: Some mutations are passed down from parents.

Types of Gene Mutations

Point mutations: A single DNA letter is changed.

Insertion: Extra DNA letters are added.

Deletion: DNA letters are removed.

Duplication: Sections of DNA are copied more than once.

Effects of Gene Mutations

Mutations can have different outcomes depending on where they occur and how they alter the gene.

No effect: Many mutations change nothing.

Helpful: Some mutations improve survival and drive evolution.

Harmful: Others can disrupt normal cell function.

Examples in Nature

Adaptation: Mutations that help species survive, like antibiotic resistance in bacteria.

Variation: Differences in eye color, height, or traits across individuals.

How Cells Handle Mutations

Cells have repair systems that fix most DNA errors. Only a small percentage of mutations remain permanent.

Why Gene Mutations Matter

They create genetic diversity, drive evolution, and help scientists understand how life changes over time.

The Simple Takeaway

A gene mutation is a change in DNA. It can be neutral, helpful, or harmful—and it plays a major role in how species evolve and vary.